Chimpanzees are forcing us to redefine what it means to be human

A
chimpanzee drinks beverage to cool off the summer
heat.REUTERS/China
Daily

Primatologist Frans de Waal says chimpanzees can do almost
everything that was once considered a distinctively human trait.

The idea that only humans make tools is today "an unsustainable
position," de Waal writes by email. "Then we also got the
apes-have-no-theory-of-mind claims, which now have been seriously
weakened, the culture claims, the idea that only humans are great
at cooperation, and so on, none of which really holds up."

The only unique trait of humans, he says, might be that we have
symbolic language.

De Waal’s latest book—"Are
We Smart Enough to Know How Smart Animals
Are?"—describes a monumental shift in our
understanding of animal intelligence in recent decades. In one
fascinating part, he takes on a theory about tools by
pointing to new observations of chimps, a species that shares 99%
of the same DNA as humans.

Anthropologist Kenneth Oakley laid out the old viewpoint in
his 1957 book, "Man the Toolmaker," which argued that mankind was
the only animal that systematically made tools.

That stance was challenged by anthropologist Jane Goodall’s
observations of chimps in the wild. When, in 1960, she described
chimps stripping leaves from a stem to make a tool to dig for
termites, her colleague Louis Leakey telegrammed: "Now we must
redefine tool, redefine Man, or accept chimpanzees as humans."

Still, Oakley wasn’t convinced. In subsequent writings,
he dismissed Goodall’s observations as "a far cry from the
systematic making of stone tools, the earliest known examples of
which … evidently require much premeditation, a high order of
skill and an established tradition implying some means of
communication."

Thus, whether man is the only true tool-making animal remained an
open question. Yet today, per de Waal, we can answer with a
definitive no.

De Waal, the director of the Living Links Center at the Yerkes
National Primate Research Center in Atlanta, Georgia and a
professor at Emory University, lays out overwhelming examples of
complex tool use by chimps. For instance:

—Chimps in the Congo have been repeatedly observed traveling with
a combination of two sticks—a meter-long sapling and a flexible
slender stem—which they use for digging into an ant nest and
grabbing ants.

—Chimps in Gabon have been repeatedly observed hunting for honey
with a five piece toolkit, including a stick for breaking open a
hive, a stick for perforating the honey chamber, a stick for
widening the opening, a stick with a frayed end for dipping into
honey, and strips of bark to scoop honey up—all tools that are
prepared and carried to the hive before the work begins.

—Chimps in one community are known to use pointed sticks to hunt,
jabbing them into a tree cavity to kill a sleeping bush baby.

All told, per de Waal, chimpanzees communities tend to use
between 15 and 25 tools, many of them prepared ahead of time with
techniques that are passed from generation to generation.

Although chimps make and use tools to a greater degree than other
non-human species, plenty of species—from gorillas to elephants
to otters to crows—have shown they can use tools too. All of that
weakens the idea of homo faber ("man the maker"), which claims
that we have a unique ability to control the environment through
tools.

As for other supposedly special traits of humans, de Waal says
they have fallen one by one: chimps and other species have been
observed showing empathy, regret, and friendship; recognizing
faces; recognizing themselves in a mirror; understanding when
other creature know or don’t know something; remembering
distant events; exercising self-restraint; and more.

It may, again, be only in language that humans are unique: "We
honestly have no evidence for symbolic communication, equally
rich and multifunctional as ours, outside our species." de Waal
writes in the book.

Whatever the differences between humans and the rest, there are
clearly fewer than we once thought. Charles Darwin may have
said in best in a quote featured by de Waal: "The difference in
mind between man the higher animals, great as it is, certainly is
one of degree and not of kind."